Gales and high seas forecast for Sydney

Gale force winds and heavy rain are predicted for Sydney tomorrow, as an east coast low hits New South Wales.

Tom Saunders from the Weather Channel says winds could gust up to 100 kilometres per hour in the afternoon and evening.

He said the wind will increase from tomorrow morning but the worst weather will be after lunch.

"There'll be severe weather warnings for Sydney issued tomorrow afternoon and evening and an absolutely massive swell - it'll increase to over five metres by tomorrow night," he said.

Mr Saunders says the low is making its way up the coast.

"Today it's in eastern Bass Strait, it's going to be moving north up the coast tomorrow," he said.

"So for Sydney tomorrow, winds will increase through the morning and then rain will develop probably around the middle of the day tomorrow afternoon and tomorrow evening will see the worst of the weather."

The Bureau of Meteorology's duty forecaster Jane Golding says big waves and a high tide could affect coastal areas vulnerable to flooding.

"There's quite a large pulse of waves coming up behind that system as well," he said.

"That in combination with the already high tides we've got at the moment its likely to lead to some local inundation and some coastal erosion for coastal areas south of about Newcastle by the end of tomorrow."